Modular diode laser assembly

ABSTRACT

An extremely versatile diode laser assembly is provided, the assembly comprised of a plurality of diode laser subassemblies mounted to a stepped cooling block. The stepped cooling block allows the fabrication of a close packed and compact assembly in which individual diode laser subassembly output beams do not interfere with one another.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/313,068, filed Dec. 20, 2005, now U.S. Pat. No. 7,436,868and claims the benefit of U.S. Provisional Patent Application Ser. No.60/739,185, filed Nov. 22, 2005, the disclosures of which areincorporated herein by reference for any and all purposes.

FIELD OF THE INVENTION

The present invention relates generally to semiconductor lasers and,more particularly, to a laser assembly that permits the output frommultiple diode lasers to be effectively and efficiently combined.

BACKGROUND OF THE INVENTION

High power diode lasers have been widely used in industrial, graphics,medical and defense applications. The beam divergence and the relativelylow output power of such lasers has, however, limited their usefulness.

The output beam of a diode laser is asymmetric due to the beam having ahigher angular divergence in the direction perpendicular to the diodejunction of the emitter (i.e., the fast axis of the emitter) than in thedirection parallel to the diode junction (i.e., the slow axis of theemitter). As a result of the differences in beam divergence, the crosssection of the output beam of a diode laser has an elliptical shape,typically requiring the use of a cylindrical lens or other optics toalter the divergence characteristics and shape the output beam for itsintended use. Although beam optics can be used on individual diodelasers, in the past the use of such optics has made it difficult tocombine multiple diode laser beams into a single beam of sufficientoutput power to suit many applications.

One method of combining the output beams from multiple lasers isdisclosed in U.S. Pat. No. 4,828,357. As shown, the output from eachlaser is directed using multiple mirrors in order to form a bundle ofparallel beams or to cause the beams to converge into a relativelynarrow region. The patent discloses that if greater power is requiredthan can be generated by a single beam bundle, multiple bundles ofparallel beams can be combined to form a beam bundle of even greaterpower. The patent does not specifically disclose the use of laser diodesnor does the patent disclose altering the beam shape of the individuallaser beams prior to directing the beams into the beam bundle.

U.S. Pat. No. 6,075,912 discloses an alternate technique for combiningthe output beams from multiple lasers into a single beam. In thedisclosed system the output beam of each laser impinges on a discretefacet of a multi-faceted beam deflector. By properly positioning eachlaser relative to the facets of the beam deflector, all of the outputbeams are deflected into an optical fiber. The patent disclosesinterposing an optical system between each laser source and thecorresponding beam deflector facet in order to properly image the outputbeam onto the deflector facet. The patent also discloses interposing anoutput optical system between the beam deflector and the optical fiber,the output optical system imaging the deflected output beams as afocused group of beam images into the core of the input face of theoptical fiber.

U.S. Pat. No. 4,716,568 discloses a laser array assembly formed from aplurality of linear diode laser array subassemblies stacked one abovethe other, each of the subassemblies electrically connected to theadjacent subassembly. Each linear diode laser array subassembly is madeup of a plurality of individual laser emitters mounted in thermalcommunication with a conductive plate. Although the patent disclosesseveral ways of stacking the subassemblies in order to form the desired2-D laser array, the patent does not disclose any optical systems foruse in combining the output beams of the individual emitters and/orsubassemblies.

U.S. Pat. No. 5,887,096 discloses an optical system that is used toguide the output beams from a rectilinear diode laser array to form asubstantially uniform radiation field or pattern. In one disclosedembodiment, the optical system utilizes a plurality of reflectors whereeach reflector corresponds to an individual diode laser. In a preferredembodiment, the centers of the irradiated surface areas of theindividual reflectors are situated in a straight line with the distancebetween a reflector and the corresponding diode laser exit facet beingthe same for each diode laser/reflector pair.

U.S. Pat. No. 6,240,116 discloses a diode laser array designed toachieve high beam quality and brightness. In one embodiment, the arrayincludes a pair of diode arrays in which the emitting surface planes ofthe two arrays are displaced from one another in a direction parallel tothe one of the optical axes defined by the arrays. The optical axes ofthe two arrays are offset from each other in a direction perpendicularto one of the optical axes. Lenses are used to reduce the divergence ofthe output beams. In at least one embodiment, reflectors are used toreduce or eliminate the dead spaces between adjacent collimated beams.

Although a variety of diode laser arrays and beam combining systems havebeen designed, what is needed in the art is a versatile diode laserassembly which can be easily tailored to specific application needs. Thepresent invention provides such a diode laser assembly.

SUMMARY OF THE INVENTION

The present invention provides a diode laser assembly comprised of aplurality of diode laser subassemblies mounted to a stepped coolingblock. The stepped cooling block is comprised of two adjacent sections,with each section including a plurality of mounting surfaces arranged ina stepped, or staircase, fashion. The mounting surfaces of the twoadjacent sections are non-coplanar with the mounting surfaces of one ofthe sections being higher than the adjacent mounting surfaces of theother section. In at least one embodiment, mounted to the mountingsurface of each step of the upper section of the stepped cooling blockis a diode laser subassembly. In at least one other embodiment, mountedto the mounting surface of each step of the lower section of the steppedcooling block is a diode laser subassembly.

Each diode laser subassembly of the diode laser assembly includes amounting block which, during diode laser subassembly mounting, isthermally coupled to the corresponding mounting surface of the coolingblock. Mounted to a surface of the mounting block is a diode lasersubmount. The diode laser submount can be fabricated from either anelectrically insulating material or an electrically conductive material.Mounted to a surface of the diode laser submount is the diode laser. Thediode laser can be either a single emitter diode laser or amulti-emitter diode laser. In at least one embodiment the diode lasersubmount includes a pair of contact pads that are electrically coupledto the diode laser, thus providing a means of supplying power to theindividual lasers.

In at least one preferred embodiment of the invention, a clamping membercompresses each diode laser submount against the corresponding mountingblock, and the mounting block against the corresponding mounting surfaceof the cooling block. Preferably the clamping members are held in placewith bolts coupled to the cooling block. The clamping members preferablyhold electrical interconnects against electrical contact pads located onthe diode laser submounts. In an alternate embodiment of the invention,at least one threaded means (e.g., bolt, all-thread and nut assembly,etc.) attaches each diode laser subassembly to the correspondingmounting surface of the cooling block.

In at least one preferred embodiment of the invention, a beamconditioning lens is attached, for example by bonding, to each diodelaser subassembly mounting block such that the output beam(s) of thediode laser passes through the lens. In one embodiment the beamconditioning lens is a cylindrical lens. Preferably a second beamconditioning lens is also attached, for example by bonding, to eachdiode laser subassembly mounting block such that the output beam(s) ofthe diode laser from a different diode laser subassembly passes throughthe lens. The different diode laser subassembly can be an adjacentsubassembly. Alternately one or more diode laser subassemblies can belocated between the second beam conditioning lens and the subassemblycontaining the diode laser that produces the output beam that passesthrough the second beam conditioning lens.

In at least one embodiment of the invention, a cooling source is coupledto the cooling block. The cooling source can be coupled to the coolingblock bottom surface, one or more cooling block side surfaces, or both.The cooling source can be integrated within the cooling block. Thecooling block can have a flat bottom surface, thus creating differentseparation distances between each diode laser subassembly mountingsurface of the cooling block and the cooling block bottom surface.Alternately the cooling block can have an inclined bottom surface, thuscausing the separation distances between each diode laser subassemblymounting surface of the cooling block and the cooling block bottomsurface to be the same.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the primary components of a diode lasersubassembly in accordance with the invention;

FIG. 2 is a perspective view of the assembled diode laser subassembly ofFIG. 1, minus the second conditioning lens;

FIG. 3 is a perspective view of the assembled diode laser subassembly ofFIG. 1, including the second conditioning lens associated with another(not shown) diode laser subassembly;

FIG. 4 illustrates the relationship between the second conditioning lensand a specific diode laser subassembly;

FIG. 5 illustrates the relationship between the second conditioning lensand a specific diode laser subassembly different from that shown in FIG.4;

FIG. 6 is an illustration of a diode laser subassembly similar to thatshown in FIGS. 1-3, utilizing a three-stripe diode laser rather than asingle stripe diode laser;

FIG. 7 is an illustration of a cooling block for use with a diode lasersubassembly such as those shown in FIGS. 1-6;

FIG. 8 is an illustration of a cooling block in which multiple diodelaser subassemblies are clamped to the upper cooling block section;

FIG. 9 is an illustration of a cooling block in which multiple diodelaser subassemblies are clamped to the lower cooling block section;

FIG. 10 illustrates a cooling block with an inclined cooling plane;

FIG. 11 illustrates a cooling block configured to accommodate two rowsof diode laser subassemblies;

FIG. 12 illustrates portions of a diode laser subassembly that utilizesan electrically conductive submount;

FIG. 13 illustrates portions of a diode laser subassembly that utilizesa pair of attachment bolts;

FIG. 14 illustrates portions of a diode laser subassembly that utilizesa single attachment bolt; and

FIG. 15 is a cross-sectional view of a cooling block/mounting block thatillustrates an alternate subassembly mounting arrangement.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides the system designer with the means totailor a diode laser assembly to the specific needs of a particularapplication. In order to provide this versatility, the system utilizes adiode laser subassembly that can be mounted in a variety ofconfigurations.

FIGS. 1-3 illustrate a diode laser subassembly utilizing a singleemitter diode laser 101. In addition to the diode laser 101, the primarycomponents associated with the diode laser subassembly are thesubassembly mounting block 103, submount 105, first conditioning lens107 and second conditioning lens 109. As described in detail below,although second conditioning lens 109 is mounted to subassembly mountingblock 103, it is used with the output beam of a diode laser mounted toanother diode laser subassembly that is not shown in FIGS. 1-3.

Subassembly mounting block 103 serves several functions. First, itprovides an efficient thermal path between diode laser 101 and thecooling block which is shown in later figures. Second, it provides aconvenient means for registering the various components of the diodelaser assembly, thereby lowering the manufacturing costs associated withthe overall assembly. Third, it provides a convenient means forregistering the individual diode laser subassemblies within the coolingblock as shown below. In order to provide the desired diode lasercooling, preferably subassembly mounting block 103 is fabricated from amaterial with a high coefficient of thermal conductivity (e.g., copper).

Diode laser 101 is not attached directly to subassembly mounting block103, rather it is mounted to submount 105. Preferably submount 105 aswell as the means used to attach submount 105 to mounting block 103 areboth materials with a high coefficient of thermal conductivity, thusinsuring that the heat produced by diode laser 101 is efficientlycoupled to mounting block 103. Additionally the coefficient of thermalexpansion for the material selected for submount 105 is matched, to thedegree possible, to diode laser 101 in order to prevent de-bonding ordamage to the laser during operation. In at least one embodiment of theinvention, submount 105 is soldered to mounting block 103 using indiumsolder.

Submount 105 can be fabricated from either an electrically conductive(e.g., copper, copper tungsten, etc.) or an electrically insulative(e.g., aluminum nitride, beryllium oxide, CVD diamond, silicon carbide,etc.) material. In the embodiment illustrated in FIGS. 1-3, submount 105is fabricated from an electrically insulating ceramic. The material usedto bond diode laser 101 to submount 105 is selected, at least in part,on the composition of submount 105 and/or the composition of any layers(e.g., contact pads) interposed between submount 105 and diode laser101. In the illustrated embodiment, electrically conductive contact pads111/113 are deposited or otherwise formed on the top surface of submount105. Contact pads 111/113 can be formed, for example, of gold overnickel plating while a gold-tin bonding material can be used to bonddiode laser 101 to contact pad 113. It will be appreciated that thereare a variety of materials well known in the industry that are suitablefor use as contact pads as well as diode laser bonding material.

In a preferred embodiment of the invention, one contact (e.g., anode) ofdiode laser 101 is on its bottom surface, thus allowing one diodecontact to be made by bonding the diode laser to one of the contact pads(e.g., pad 113) using an electrically conductive material. A wire bondor ribbon bond 115 is then used to electrically couple the secondcontact (e.g., cathode) of each diode laser to the second contact pad111. It will be appreciated that the invention is not limited to thiscontact arrangement. For example, a pair of wire or ribbon bonds can beused to couple the diode laser to a pair of contact pads.

First conditioning lens 107, which in at least one embodiment is acylindrical lens, is properly positioned relative to diode laser 101using the extended arm portions 117 and 119 of mounting block 103.Typically lens 107 is located immediately adjacent to the exit facet ofdiode laser 101. Once lens 107 is properly positioned, it is bonded intoplace. The purpose of conditioning lens 107 is to reduce the divergenceof diode laser 101 in the fast axis, preferably to a value that is thesame as or less than the divergence in the slow axis.

In order to properly condition the output beam of diode laser 101,preferably a second conditioning lens 109 is used. It should beunderstood that the specific second conditioning lens 109 shown in FIGS.1-3, although mounted to the top surfaces 121 and 123 of respective armportions 117 and 119, is not used to condition the beam from theillustrated diode laser 101. Rather the illustrated conditioning lens109 is used to condition the output beam from an adjacent diode lasersubassembly (e.g., beam 401 in FIG. 4), or the output beam from a diodelaser subassembly that is more than one subassembly removed from thesubassembly (e.g., beam 501 in FIG. 5). It will be appreciated that thefocal length of second conditioning lens 109 as well as the height ofarm portions 117 and 119 is dependent on which diode laser output beamis intended to pass through which second conditioning lens (i.e., thenumber of diode laser subassemblies separating the second conditioninglens from the diode laser source).

Although the diode laser subassembly shown in FIGS. 1-5 utilizes asingle emitter, the present invention is equally applicable tomulti-emitter diode lasers. For example, FIG. 6 is an illustration of adiode laser subassembly utilizing a three-stripe diode laser 601. Due tothe size of diode laser 601, the contact pads 603/605 on submount 607are typically of a different size than those on submount 105 used withthe single emitter diode laser. Additionally the second conditioninglens (i.e., lens 609) is multi-faceted (i.e., facets 611-613) in orderto properly condition the individual output beams of diode laser 601.

FIG. 7 is a perspective view of a preferred cooling block 700 for usewith the previously described diode laser subassemblies. As shown,cooling block 700 includes two adjacent sections 701 and 703, with oneof the sections (i.e., section 701) raised relative to the other section(i.e., section 703). Both the mounting surfaces 705 of upper section 701and the mounting surfaces 707 of lower section 703 are formed in astaircase, or stepped, fashion. As shown, adjacent mounting surfaces ofthe two sections are non-coplanar with the mounting surfaces of one ofthe sections being higher than the adjacent mounting surfaces of theother section.

The previously described diode laser subassemblies can be mounted toeither upper section 701 or lower section 703 of cooling block 700.Either section provides a plurality of the desired stair-steppedmounting surfaces, thus allowing the subassemblies to be verticallyoffset from one another such that the output beams from the diode lasersubassemblies can exit the assembly unimpeded.

Exemplary embodiments are shown in FIGS. 8 and 9. In FIG. 8 five diodelaser subassemblies 801-805 are positioned on the upper mountingsurfaces (e.g., surfaces 705) of cooling block 807 while in FIG. 9 fivediode laser subassemblies 901-905 are positioned on lower mountingsurfaces (e.g., surfaces 707) of cooling block 907. In the illustratedembodiments, the second conditioning lens for each subassembly islocated on the arm portions of the adjacent subassembly mounting block.It will be appreciated that in the illustrated embodiments the uppermostsubassembly, i.e., subassembly 801 in FIG. 8 and subassembly 901 in FIG.9, does not include a second conditioning lens and that the secondconditioning lens for the lowermost subassembly, i.e., subassembly 805in FIG. 8 and subassembly 905 in FIG. 9, is simply mounted to a standalone lens carrier, i.e., lens carrier 809 in FIG. 8 and lens carrier909 in FIG. 9. The stand alone lens carrier, i.e., carrier 809 or 909,can either be integral to the cooling block, i.e., machined from thesame material, or it can be an independent carrier that is mounted tothe cooling block.

Although any of a variety of means can be used to mount thesubassemblies to the cooling block, in the embodiments illustrated inFIGS. 8 and 9 each diode laser subassembly is clamped to the coolingblock with a clamp member, i.e., clamp members 811 in FIG. 8 and clampmembers 911 in FIG. 9. The clamp members hold the diode lasersubassemblies in place and insure that good thermal contact is madebetween subassembly mounting blocks 103 and the cooling block. Dependingupon the size of the clamping members as well as the location of thesubassembly contact pads (e.g., pads 111/113), the clamping members canalso be used as a means of electrically contacting one or both contactpads. The clamping members can either make electrical contact throughdirect contact or by pressing an electrical contact against one or bothpads, the electrical interconnect being interposed between the clampingmembers and the contact pads on the submounts. During use, preferablyeither the cooling block is thermally coupled to a cooling source (e.g.,thermoelectric cooler), or the cooling source is integrated within thecooling block (e.g., integral liquid coolant conduits coupled to asuitable coolant pump).

As the cooling block (e.g., blocks 807 and 907) is comprised of a seriesof steps onto which the diode laser subassemblies are mounted, thecooling rate and thus the operating temperature of the individual lasersubassemblies varies depending upon the distance between the coolingsource coupled to the cooling block and the individual subassemblies.Since the operating wavelength of a diode laser is temperaturedependent, the inventors have found that the operating temperaturevariations between subassemblies that arise due to the stepped coolingblock and the use of a bottom mounted cooling source can be used tomatch diode laser subassembly wavelengths. Accordingly in at least oneembodiment of the invention, the output wavelength of each subassemblyis determined based on the subassembly's position on the cooling block.Then each subassembly is positioned on the cooling block to provide theclosest possible match to the desired output wavelength of the entireassembly.

Although the figures described above illustrate at least one preferredembodiment of the invention, it will be appreciated that there arenumerous minor variations that are clearly envisioned by the inventors.For example, FIG. 10 illustrates an alternate embodiment of a coolingblock in which the bottom surface 1001 of the cooling block is inclined.As a result of this configuration, each mounting surface is the samedistance from the bottom surface 1001, thus maintaining the same coolingrate for each mounted diode laser subassembly (not shown) even whenthermally coupling the cooling source to the bottom surface (i.e.,surface 1001) of the cooling block.

In the above figures, the illustrated exemplary configurations includeonly a single row of subassemblies. It should be appreciated, however,that assemblies in accordance with the invention can include either moreor less than the five diode laser subassemblies shown in FIGS. 8 and 9.Additionally, assemblies that contain more than a single row of diodelaser subassemblies can be fabricated using the present invention. Forexample, FIG. 11 illustrates a cooling block 1100 that can be used witha total of ten diode laser subassemblies, five per row. The output beamfrom each row can either be combined using known optical techniques, orthe assembly can be used to produce two separate output beams.

As previously noted, the diode laser subassemblies of the presentinvention can utilize either electrically insulating or electricallyconducting submounts as well as any of a variety of different diodelaser contacting arrangements. Thus the submount/contact arrangementshown in FIGS. 1-3 and 6 is only an exemplary configuration and shouldnot be viewed as a limitation of the present invention. For example,FIG. 12 illustrates portions of a diode laser subassembly that utilizean electrically conductive submount 1201. In this embodiment diode laser101 is attached to submount 1201 with an electrically and thermallyconductive solder or bonding material. As a consequence, one contact todiode laser 101 is made via electrically conductive submount 1201,directly or via subassembly mounting block 103 and/or the cooling block(not shown). Of course if electrical contact is made via subassemblymounting block 103, then an electrically conductive solder or bondingmaterial must be used to attach submount 1201 to the subassemblymounting block. Similarly if electrical contact is made via the coolingblock (not shown), then an electrically conductive solder or bondingmaterial must be used both to attach submount 1201 to the subassemblymounting block and to attach the subassembly mounting block to thecooling block. The second contact to the diode laser is made via acontact pad 1203, each diode laser being connected to contact pad 1203via a wire bond or ribbon bond 1205.

Although FIGS. 8 and 9 illustrate the use of clamping members to holdthe subassemblies to the cooling block, as previously noted there arenumerous other techniques that can be used to mount the subassemblies.For example, FIG. 13 shows a partial diode laser subassembly 1300 inwhich a first bolt 1301 holds contact pad 1303 and submount 1305 as wellas mounting block 1307 to the cooling block (not shown) while a secondbolt 1309 holds contact pad 1311 and submount 1305 as well as mountingblock 1307 to the cooling block (not shown). Preferably in thisconfiguration submount 1305 is fabricated from an electricallyinsulating material.

In addition to the above-described approaches, it will be appreciatedthat there are numerous mounting techniques that can be used to mountthe diode laser subassemblies to the cooling block, these techniquesusing various arrangements of clamping members, bolts and/or bondingmaterials (e.g., solder, adhesive). For example in the embodimentillustrated in FIG. 14, a single bolt 1401 is used to attach mountingblock 1403 to the underlying cooling block (not shown). Submount 1405 isattached to mounting block 1403 by solder or an adhesive. Preferably apair of contact pads 1407/1409 is used to electrically couple to diodelaser 101. In an alternate embodiment illustrated in FIG. 15, at leastone bolt 1501 attaches each mounting block 1503 to cooling block 1505,the bolts passing through the bottom of the cooling block and beingscrewed into the bottom of mounting blocks 1503.

As will be understood by those familiar with the art, the presentinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. Accordingly, thedisclosures and descriptions herein are intended to be illustrative, butnot limiting, of the scope of the invention which is set forth in thefollowing claims.

1. A diode laser assembly comprising: a stepped cooling block, saidstepped cooling block comprising a first cooling block section and anadjacent second cooling block section, wherein each of said first andsecond cooling block sections includes a plurality of stepped mountingsurfaces of increasing height relative to a plane corresponding to alowermost portion of a cooling block bottom surface, wherein adjacentstepped mounting surfaces of said first and second cooling blocksections are non-coplanar with said stepped mounting surfaces of saidfirst cooling block section positioned lower than said adjacent steppedmounting surfaces of said second cooling block section; a plurality ofdiode laser subassemblies, wherein each of said diode lasersubassemblies is comprised of: a mounting block; an electricallyinsulating diode laser submount mounted to said mounting block, whereinsaid diode laser submount is comprised of an electrically insulatingmaterial; a diode laser mounted to said diode laser submount, whereinsaid diode laser is a single emitter diode laser; a first beamconditioning lens mounted to said mounting block, wherein an output beamfrom said diode laser passes through said first beam conditioning lens;and a second beam conditioning lens mounted to said mounting block,wherein a second output beam from a different diode laser subassembly ofsaid plurality of diode laser subassemblies passes through said secondbeam conditioning lens; and means for mounting each of said plurality ofdiode laser subassemblies onto corresponding stepped mounting surfacesof said plurality of stepped mounting surfaces of said first coolingblock section of said stepped cooling block, wherein each output beamfrom said plurality of diode laser subassemblies is displaced relativeto an adjacent output beam.
 2. The diode laser assembly of claim 1,wherein each of said first beam conditioning lenses comprises acylindrical lens.
 3. The diode laser assembly of claim 1, wherein saiddifferent diode laser subassembly is adjacent to said diode lasersubassembly comprising said second beam conditioning lens.
 4. A diodelaser assembly comprising: a stepped cooling block, said stepped coolingblock comprising a first cooling block section and an adjacent secondcooling block section, wherein each of said first and second coolingblock sections includes a plurality of stepped mounting surfaces ofincreasing height relative to a plane corresponding to a lowermostportion of a cooling block bottom surface, wherein adjacent steppedmounting surfaces of said first and second cooling block sections arenon-coplanar with said stepped mounting surfaces of said first coolingblock section positioned lower than said adjacent stepped mountingsurfaces of said second cooling block section; a plurality of diodelaser subassemblies, wherein each of said diode laser subassemblies iscomprised of: a mounting block; an electrically insulating diode lasersubmount mounted to said mounting block, wherein said diode lasersubmount is comprised of an electrically insulating material; a diodelaser mounted to said diode laser submount, wherein said diode laser isa single emitter diode laser; and means for mounting each of saidplurality of diode laser subassemblies onto corresponding steppedmounting surfaces of said plurality of stepped mounting surfaces of saidfirst cooling block section of said stepped cooling block, wherein eachoutput beam from said plurality of diode laser subassemblies isdisplaced relative to an adjacent output beam, wherein said mountingmeans further comprises a plurality of clamping members attached to saidplurality of stepped mounting surfaces of said second cooling blocksection of said stepped cooling block, wherein said plurality ofclamping members corresponds to said plurality of diode lasersubassemblies.
 5. The diode laser assembly of claim 4, wherein eachclamping member of said plurality of clamping members compresses aportion of each diode laser submount against a portion of each mountingblock of each corresponding diode laser subassembly of said plurality ofdiode laser subassemblies and compresses said portion of each mountingblock against a portion of each corresponding stepped mounting surfaceof said first cooling block section.
 6. The diode laser assembly ofclaim 5, wherein each clamping member of said plurality of clampingmembers compresses at least one electrical interconnect against at leastone electrical contact pad on said portion of each diode laser submount.7. The diode laser assembly of claim 4, further comprising a pluralityof bolts corresponding to said plurality of clamping members, whereinsaid plurality of bolts are attached to said plurality of steppedmounting surfaces of said second cooling block section of said steppedcooling block.
 8. A diode laser assembly comprising: a stepped coolingblock, said stepped cooling block comprising a first cooling blocksection and an adjacent second cooling block section, wherein each ofsaid first and second cooling block sections includes a plurality ofstepped mounting surfaces of increasing height relative to a planecorresponding to a lowermost portion of a cooling block bottom surface,wherein adjacent stepped mounting surfaces of said first and secondcooling block sections are non-coplanar with said stepped mountingsurfaces of said first cooling block section positioned lower than saidadjacent stepped mounting surfaces of said second cooling block section;a plurality of diode laser subassemblies, wherein each of said diodelaser subassemblies is comprised of: a mounting block; a diode lasersubmount mounted to said mounting block; and a diode laser mounted tosaid diode laser submount; a first beam conditioning lens mounted tosaid mounting block, wherein an output beam from said diode laser passesthrough said first beam conditioning lens; a second beam conditioninglens mounted to said mounting block, wherein a second output beam from adifferent diode laser subassembly of said plurality of diode lasersubassemblies passes through said second beam conditioning lens; andmeans for mounting each of said plurality of diode laser subassembliesonto corresponding stepped mounting surfaces of said plurality ofstepped mounting surfaces of said first cooling block section of saidstepped cooling block, wherein each output beam from said plurality ofdiode laser subassemblies is displaced relative to an adjacent outputbeam.